The Animal Research Facility of the National Institute of Public Health and Environment (RIVM, The Netherlands) has, in collaboration with the different research projects in this PPG, successfully conducted several longevity and cross sectional studies with mice having a defect in DNA repair and/or RNA transcription. Some of these mouse strains showed phenotypes of accelerated aging. As part of the present program renewal application the animal and pathology core will continue to conduct such studies, but will now have a more specific focus (based on the results obtained in the previous grant period) and will include intervention studies. On the basis of anticipated results of the 5 projects, intervention strategies will be developed in our mouse models, e.g. to eradicate senescent cells and to ameliorate ageing phenotypes through pharmaceutical and/or nutraceutical interventions. Overall, the specific aims of the animal/pathology core are: 1. To ensure uniformity and homogeneity of animals and the environment in which the animals will be housed;consequently the animals will be backcrossed into the same genetic C57BL/6JxFVB F1 hybrid background. 2. To ensure that the animals are raised in a pathogen free environment. 3. To facilitate the sharing of animals, tissues and cells among the individual investigators. 4. To conduct longevity and/or cross sectional studies with various single and double mutant or transgenic mouse models of interest to the consortium. 5. To conduct life-span intervention studies with short-lived progeroid mouse models, with one or two added cross sectional studies for the most promising interventions in mutant and wild type mice. To conduct full histopathology on all animals from the longevity studies and if necessary also on mice from the cross sectional studies. To make mutagenesis studies possible, all transgenic mouse lines will be crossed with lacZ containing pUR288 transgenic mice.